Rotation spring: Rotation symmetric compression-torsion conversion structure with high space utilization

Abstract

In recent years, forefront researchers came up with the idea of compression-torsion conversion (CTC) via structure design, which brought us a new research direction of mechanical metamaterials. Generally designed CTC structures could be categorized as array-type or cylindrical-shell-type. They all designed to realize CTC but featuring some obvious defects. In this paper, a novel structure named rotation spring with great symmetry and high space utilization is proposed. Firstly, the theory and new design method of the CTC structure is proposed. Secondly, the curved surface composing the rotation spring is designed based on our new design method and geometrical calculations. Moreover, theoretical calculations, numbers of finite-element simulations are employed to study characteristics of the proposed structure with different geometrical parameters under axial strain. Finally, specimens of rotation spring are fabricated utilizing 3D printing technology for compressive tests. The main factors affecting the torsion angle of the proposed structure are discussed in detail. It is found that the rotation spring features excellent performance in CTC, which indicates great potential for application in fields of machinery, vehicle engineering, and power generation.